HONG KONG: Patients in the city infected with A (H1N1) influenza are being warned about possible adverse reactions from taking anti-viral drugs. The caution comes after a recent report revealed that tamiflu is suspected to have been associated with two deaths in the United Kingdom (UK).

Although Hong Kong has no reports of such adverse reaction, the Practising Pharmacists Association of Hong Kong (PPAHK) said that high risk groups such as pregnant women, the elderly and patients with liver diseases will be more prone to adverse side effects.

"No medicine is completely safe. Patients must not buy or take the anti-viral drugs without a doctor's prescription; otherwise it could cause fatal consequences," said Iris Chang, president of the association.

According to the report from the UK's Medicines and Healthcare products Regulatory Agency (MHRA), 533 reports of suspected adverse reactions to tamiflu and 12 for relenza were recorded in the UK between April 1 and August 13.

However, the report stressed that no scientific evidence has proved that the drugs were the direct cause of the side effects and that the reaction might have been caused by concurrent illness.

Several cases involved interaction between tamiflu and warfarin, a drug used to prevent formation of blood clots. Patients who were affected suffered from prolonged blood clotting. Chang noted there could be bruises and excessive blood loss. She cautioned that since most senior citizens take warfarin to prevent heart attacks and stroke, they must pay careful attention to any abnormal reaction.

The 12 reports of undesirable effects associated with relenza were common allergic reactions, except in the a case of a miscarriage during early pregnancy.

"However, the benefits of using the anti-viral drugs to treat pregnant women still outweigh the suspected risk," said Godfrey Lui, PPAHK's vice president.

Chang expects that reports of adverse side effects from the drugs will emerge in Hong Kong in the near future, as more people come down with the rapidly spreading human swine flu.

As the new academic year starts next week, the PPAHK advised parents to prepare facial masks and alcohol gel for their children.

Lui reminded parents that young kids must not take aspirin which may damage the central nervous system of children.

(HK Edition 08/28/2009 page1)